ABSTRACT The goal of this proposal is to answer a fundamental question in nursing: Is there a compelling case (with respect to quality, cost, and value) for improving the nurse work environment? Answering this question in a clear and transparent manner would have a profound impact on guiding management and resource allocation in our healthcare system. To accomplish this goal, we will examine ?comparative advantage? across nursing environments. Through the use of new methods in multivariate matching, we aim to compare outcomes (quality, cost, and value) for similar matched patients in different nursing environments, and different groups of patients in the same nursing environment. We define a set of nursing environments based on our NINR-funded nurse survey data and information from other sources. We ask whether such environments produce comparative advantage (in terms of quality, cost, and value) treating specific types of patients (say, different risk levels for specific diagnoses) versus different nursing environments with a closely matched set of patients, while matching exactly on other hospital characteristics. We will explore what types of patients benefit most from ?better? nursing environments, and conversely, what types of patients are most vulnerable to ?worse? nursing environments. Patients will be matched on 30 to 50 patient covariates simultaneously. We will then test for outcome synergy (the interaction between patient risk and nursing environment) using patient outcomes data and resource use information from Medicare and other sources. The study includes hospitalized patients in four states: CA, FL, NJ, and PA, admitted for acute myocardial infarction (AMI), congestive heart failure (CHF), community acquired pneumonia (CAP), stroke, sepsis, and for the surgical categories of general surgery, orthopedics, and certain high-risk procedures. The study has three aims: (AIM 1) To create a detailed, matched patient-level database corresponding to measured nurse work environments; (AIM 2) To determine comparative advantage in nursing with respect to patient quality outcomes (mortality, complications, readmissions, failure-to-rescue), cost and resource utilization (cost, ICU use, length of stay), and value (a function of both cost and quality); and (AIM 3) To determine the outcome synergies, i.e, the interactions, between nursing environments and patient risk. In the end, we will determine whether there is a compelling case for better nursing environments, and to determine if this case is different for different groups of patients. We will estimate the comparative advantage between different nursing environments, and determine specific patient groups (high or low risk over numerous outcome dimensions) that benefit from different nursing environments. If we find clear cases where specific groups of patients benefit from specific environments, such information is highly actionable: It can help nurses and hospital decision-makers better treat their patients through differential staffing, targeted nurse recruitment, and organizational changes, and help patients choose hospitals with the nursing environments identified to best meet their specific needs.